


Always Read The Manual First

by fiordilatte



Series: Then Suddenly, Cockpit Sex [1]
Category: Aldnoah.Zero (Anime)
Genre: 1st Cour AU, Cockpit Sex, Crack Treated Seriously, First time shenanigans, Fluff and Smut, Inaho is really OP, M/M, Spooning, Wow these guys are dorks
Language: English
Status: Completed
Published: 2015-02-09
Updated: 2015-02-09
Packaged: 2018-03-11 04:25:34
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,755
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/3313871
Author URL: https://archiveofourown.org/users/fiordilatte/pseuds/fiordilatte
Summary: <blockquote class="userstuff">
              <p>Slaine’s instincts betray him.  Inaho puts theory into practice.  There ARE instructions for everything, after all.</p>
            </blockquote>





	Always Read The Manual First

Slaine Troyard was conflicted.  This was nothing new to him, since morality always seemed so baseless to the sixteen year old.  Making choices was difficult.  So it was unsurprising that he wasn’t certain how he felt - or, rather, how he was supposed to feel - about the predicament he’d landed himself in.

“Orange,” he hissed, folding his arms over his chest.  The nickname sounded absurd to his own ears, but he still managed to convey a solidly annoyed tone.  

“Yes, Bat?” Kaizuka Inaho responded, his voice as flat and devoid of emotion as the first time Slaine had met him.  

They were in the sleeping berth, a small room on the ship filled with rows of neat, identical bunks.  What had started as a conversation about tactics against Martian weaponry had, due to Slaine’s paranoia, turned into yet another argument about trust issues.  Extreme trust issues.  Of the Slaine Troyard variety.     

He flushed slightly, without quite knowing why.  “I don’t believe that -”

Inaho interrupted him.  “You have no reason to be my enemy,” the brunet said.  “Seylum-san is with us.  Was she not your goal to start with?  It would not be a good tactical approach for you to betray us.  You would lose immediately, and Seylum-san would not follow you.  There would be no change in the situation... except Yuki-nee might want to lock you in a cell.”

He gritted his teeth, and jumped up from his seat on the bunk to slam the other boy into the wall.

Slaine resisted the urge to punch Inaho in the face, though he knew that he could at least match the younger boy in hand to hand combat, if it did come to that.  Brilliance notwithstanding, Kaizuka Inaho just did not have the same level of experience that Slaine did in terms of physical altercations.  Of course, though he hated to admit it, Inaho would always, always win in a Kataphrakt battle.  But in an empty, isolated room, with nothing to use as a weapon, Slaine almost surely had the upper hand.  He hoped.  That Vers military training had to give him an edge _somehow_.

“Your breathing has become erratic,” Inaho stated, his voice still calm and composed.  Brown eyes bored into his own, emotionless and unreadable.  It was rather unsettling.

Slaine scowled, digging his fingers into Inaho’s shoulders.  “Shut up,” he snapped.  His bright eyes narrowed to slits.

Inaho blinked.  Slaine stared, his hands trembling slightly.  A thin layer of perspiration formed across his forehead.  He wasn’t sure what he wanted to do, so he acted on impulse.   

Perhaps it was the stress involved in the transfer from Vers to the United Forces, but his decision making was even worse than usual today.  And he was feeling very frustrated.  Slaine leaned in, squeezed his eyes shut, and brought his lips to the younger boy’s.  It was a great idea at the time.

Almost like he’d been expecting it, Inaho tilted his head upward into the kiss, hands moving experimentally to circle Slaine’s waist.  His grip on Inaho’s shoulders slackened, and he found himself reaching to remove the shorter boy’s tie instead.  His fingers were clumsy as he grasped at the red fabric, stumbling past the knot and scrabbling for purchase.  Inaho gently steered his hand away and was kind enough to undo it himself, deftly slipping the silk from his collar as they continued to kiss.   

Unconsciously, Slaine ground his hips into Inaho’s, shoving him even harder against the wall.  He felt a tightness in his pants as his erection made itself apparent, and he heard himself groan as he pressed himself against the other boy’s thigh.  

Maybe he really had lost it.  Slaine jerked away and brought a gloved hand to his lips, his heart hammering all the while.  

“Is that all?” said Inaho, turning to make his way over to the door.  He inclined his head.  “Good talk.”

Slaine fidgeted nervously with the collar of his borrowed United Forces uniform.  “S-Sorry!” he stammered.

“Why?”

“It’s… probably not normal to suddenly have someone kiss you, is it?” he said, with a nervous laugh.  His face was scarlet from the thought of what he’d done, and he couldn’t wait for the other boy to leave.  “I don’t know what I was thinking.”

Inaho surveyed him contemplatively.  Well, Slaine assumed it was a contemplative look, though Inaho’s expression hadn’t actually changed from the moment they’d started talking.  “That’s fine,” the brunet answered, smoothing his uniform jacket down.  He seemed incredibly unfazed.  

 

* * *

 

The next encounter was all of thirty minutes later, as Slaine was exploring the ship and attempting to forget what had just happened.  He was caught off-guard when Inaho struck from behind.

The shorter boy seized him by the arm, marched him along through the corridor back to their sleeping quarters, and pinned the ex Vers soldier down on his bunk without saying a single word.  

“Get off of me!” Slaine yelled, bringing his knee up to slam into the brunet’s stomach.  A justifiable self defense maneuver, he would later argue.  

Inaho didn’t budge, though Slaine knew that it had to have winded him.  “No,” the other boy said matter-of-factly, hands clasped firmly around Slaine’s thin wrists.  Inaho stared impassively down at the blond’s flustered face.   

He couldn’t tell if this was an assassination attempt or if Inaho was just picking a fight.  Neither seemed very plausible, but Slaine decided he should be on the defensive.  One false move from Inaho, and he would strike.  

Then to his confusion, the younger boy leaned down (which should have been more difficult, considering Slaine’s knee was still planted in his stomach) and cautiously pecked him on the lips.  

Payback for before?  Not exactly conventional, but fair was fair, Slaine supposed, although being pinned to a bed wasn’t necessarily his favourite activity.  But he could deal with one kiss.  

Except now Inaho was tracing his tongue across the part in Slaine’s lips, trying to find an entrance, and he realized that he wanted much more than a kiss.  In spite of his misgivings, he instinctively lowered his leg back down, so he was flat on the bed and Inaho’s chest was flush against his own.  Inaho, noticing the shift in attitude, released his hold, hands migrating downward to unbutton the older boy’s shirt.

The Sleipnir pilot kissed him again, tongue plunging into Slaine’s mouth, wet and inquisitive.  Neither of them was very practiced, and their teeth knocked together as they explored each other, but Slaine couldn’t bring himself to care.  Strands of saliva coated his lips, and the subtle taste of citrus filled his mouth.

Inaho panted slightly against him, sliding his warm hands against Slaine’s taut skin and tracing the pale scars on his chest.  The brunet shrugged his jacket off, then reached into his schoolbag to produce a handful of condom packets, as well as a few other supplies -

Wait. 

Slaine, coming back to his senses, sat up and gaped.  Unbelievable.  What did Inaho think he was going to be getting from him?  Kissing was nice, but this was suspiciously well planned out.  And very convenient, but he couldn’t say _that_ out loud.   

“How do you just happen to have those, Orange?” he asked, pointing an accusing finger at the younger boy.  The Deucalion was a military ship, so he didn’t think they would be particularly well stocked in... condoms and lube.  At least, they shouldn’t be.  

“I took them from Calm’s bunk,” was the offhand response.  

Slaine laughed weakly, and buried his face into his hands.  “But you can’t just take his things without asking, can you?”  On Vers, that would never have gone over well.  

Inaho’s tone was very serious.  “I don’t think he’ll get a girlfriend anytime soon.  Calculated probability, zero point zero three percent.”

The blond exhaled.  Inaho was a cold, cold man.  “Your point, though?”

“I’m merely continuing from where you started, Bat.  I’d like to try going further.”

Slaine made a face, but couldn’t argue against the eager throb in his pants.  He could feel the other boy gazing pointedly at his groin.

“I need a verbal yes, Slaine.”  Inaho powered on the tablet that was sitting at the edge of his bunk.  “That’s part of the rules.”

He rolled his eyes, but had to acknowledge that it was one of the more considerate things he’d heard in a long time.  “Uh, yes,” he replied, before he could second guess himself and run for the exit.  A tiny smile twitched at the corners of his mouth, and he could feel his earlier irritation ebb away.  Most of it.

Inaho locked the door, and Slaine lunged at him, tearing the shorter boy’s shirt off with more fervor than he knew he possessed.  Boots were kicked off and pants discarded to the floor, belt buckles clattering on the cold metal surface.

“So,” he said, painfully hard.  “How does this work, anyway?”

Inaho, quite unruffled, studied his tablet diligently, in much the same way anyone else would study a grocery list.  “First, stimulate your partner.  Remove clothes.  Check.  Always remember to lubricate.  Second, insert fingers -”

“What are you doing?” Slaine lamented.  He was not especially well versed in sexual activities himself, having been locked in a Martian landing castle for the better part of his formative years.  Still, there was something that seemed… wrong with having sex straight by the books.  Or, in this case, by the tablet.  

“I’m just making sure I get this right,” Inaho explained, calmly applying lube to his fingers and making his way over to the blond.

He bit his lip but didn’t object when Inaho inserted the first finger.

“Ohh…” he mumbled, sucking in a breath.  It didn’t hurt, thanks to Inaho’s thoroughness, but it wasn’t terribly pleasant, either.  

“Okay,” said Inaho, looking him in the eye.  “Are you ready for the next one?”

He murmured his assent, and Inaho slid a second digit in, moving his fingers in gentle, circular motions.  He felt the other boy fingering the tight ring of sensitive nerves, pumping him, stretching him out.  Slaine presumed this was also some sort of textbook strategy that Inaho had found online, but he was glad that the other other boy seemed to know what he was doing.

“Nnn,” he muttered, voice huskier than he was used to hearing.  He dug his nails into his arm and pressed his back against the thin divider.  Inaho continued to add pressure, kneading, probing, and Slaine’s hand drifted to his cock as he wondered faintly if he would be able to come just like this.  

“Don’t do that,” said Inaho, pulling his fingers out with a wet pop.  “I’m prepping you for something better.”  He gestured with a condom.  “Can you put this on with your mouth?” he asked, completely straight faced.  “Yutaro mentioned that it makes things more intimate.”

Slaine’s face turned a dangerously bright shade of red.  “No!” he protested, indignation colouring his voice.  “I don’t think I can pull th-that kind of thing off.”  The words spilled out in a muddled rush. 

Inaho appeared to be in deep thought.  “Next time, then.”  He slid it on himself, without skipping a beat.  “Well, you seem to be ready.  Turn over so that you’re lying on your side.  It’s supposed to be easier for beginners that way.  And,” Inaho added, motioning to the bunk above them, “I don’t want to bump my head.”  

“Then what?” said Slaine, rolling over as he was told, the cool sheets sending goosebumps along his skin.  

He felt the other boy settle in behind him, warm and always so sure of himself.  “Then... I’m going to put it in.”  

Inaho rubbed the tip of his cock against Slaine’s entrance, then slowly pushed himself inside.

The blond gasped into the mattress, and clutched frantically at the bedsheets.  “Inaho, I can’t - just take it out - ”  Maybe this wasn’t such a good idea.  

“You’re doing fine,” Inaho informed him, “just breathe.”  The younger boy tapped at his tablet again.  “Try to relax so you can adjust.”  

“O-Okay,” Slaine responded, trying not to squeak.  He was tense.  So tense.  He took a deep breath, trying to come to terms with having Inaho inside of him.  Bit by bit, his muscles started to loosen, adjusting to accommodate the new sensation.

Inaho continued to slide himself in, slowly, gently, up to the hilt.  The younger boy moved closer so they were spooning now, his body curling up snugly against Slaine’s, and threaded his fingers through the blond’s hair.  Slaine sighed into the touch, closing his eyes as he felt himself relax.  The brunet’s chest was warm on his back, and he could feel Inaho’s heartbeat thrum against his bare skin.  

“How are you?” Inaho asked, the words hot against Slaine’s ear.  

“It’s better now,” he said, still breathing deeply.    

“Mm.  Can I move?”  Inaho stroked his hair again, a soft, methodical movement that made Slaine’s toes curl.  Inaho was much more tactile than he had expected, and it was strangely nice to know that beneath the robotic exterior, there might actually be a human.  

“I think so,” Slaine replied, trying to mentally prepare himself.  “I’m ready.”  He gripped a pillow to his chest.

Inaho pressed his lips to the slope of Slaine’s neck, then began to thrust into him, sliding in and out at an even, steady pace.  At first it was uncomfortable, and Slaine tightened with each movement, but Inaho was patient and always waited for him before he proceeded.  

Gradually he began to warm up to the feeling, and managed to loosen up enough so that the thrusts were easier and more pleasurable.  “You can go faster,” Slaine rasped, feeling himself dripping with need.  He reached back to place a sweaty hand on Inaho’s hip, guiding his movements and helping to build their new rhythm, showing the other boy precisely how he wanted to be touched.  

And just when things were finally getting really, _really_ good, just as he was nearing the edge of his climax, panting and sweating and moaning into tousled bedsheets, the alarms went off.  

“Aaagh!” he shouted, and it wasn’t in enjoyment at all.  He rolled off the bed and crashed onto the floor in his surprise.        

Of course.  If the Martians’ betrayal of Princess Asseylum weren’t reason enough, this, Slaine decided, was truly what would have ignited his loathing for the Vers Empire.  His first time, ruined.   

“Deploy all Kats immediately!” Captain Magbaredge commanded over the ship’s intercom.

Slaine really could not believe it.  In a rather undignified fashion, he scrambled to pull his clothes back on, grimacing at the sticky sensation of lube and sweat on the fabric.  

“Ah,” said Inaho, absently.  The brunet got dressed as well, seemingly no worse for the wear.  In fact, he looked exactly the same as he had before they’d started ripping each other’s clothes off.  Slaine, on the other hand, was flushed in the face and breathing heavily, and his wavy blond hair was more disheveled than ever.  

The older boy furiously wiped his hands, then pulled his gloves on.  “I guess we’d better go, then, Orange,” he muttered, trying to hide the disappointment in his voice.  

Inaho nodded, adjusting his tie.  “You’re coming with me.”

“Huh?” He gave Inaho an odd look. 

The brunet nodded again, as though agreeing to a suggestion.  “Yes, I think that would be the most efficient solution.”

Slaine’s hands balled into fists.  He hated how Inaho always seemed to withhold important information.  “What are you talking about?”

Inaho faced him squarely.  “Did you cum, Bat?”  

He froze, eyes wide in horror.  It was so bizarre to hear Inaho saying those words in such monotone.  “No, but…  What does that have to do with the current situation?” he yelped, pulling the door open and forcibly shoving the other boy out.

“Follow me,” was all that he got in reply.  

They ran down the hall, boots clicking on the metal floorboards as they made for the Kataphrakt loading bay.  Slaine started for his Sky Carrier, when Inaho grabbed him by the hand.  

“In the Kat,” the younger boy said, pointing to the orange mech.  

“But - ”

“Hello, Inaho-san, Slaine!” Princess Asseylum greeted them.  “Are you going together?”

“Yes,” Inaho responded.  He turned to acknowledge the Princess.  “We didn’t finish having sex.”  

Slaine could feel the blood rising in his cheeks, and his entire body burned.  His eyes flicked back and forth between Inaho and Asseylum, the mortification opening a pit in his stomach.  He should never have trusted Inaho.  This was far worse than any torture he had endured on Vers.   

“That - That’s a joke!” he sputtered, staring into his Princess’ wide, innocent eyes.  He needed to shield her from such debauchery.  She had to remain pure and untainted, a beacon of hope for the future!

“He’s lying,” said Inaho, failing, or just not caring, to read the situation.  Slaine felt an expectant tug at his sleeve. “Let’s go.”  

The boy blushed as Asseylum turned to him, gracing him with a dazzling smile.  “Don’t worry, Slaine.  I would like you to enjoy your time with Inaho-san.  I’m sure it will be a good experience for you both!”

He simply stared down at his hands.  All of his illusions had been destroyed.  “Forgive me,” he breathed, bowing down low.

 

* * *

 

And thusly, cockpit sex was the greatest tactical operation ever implemented.

“How are we supposed to do this?” Slaine demanded.  “It’s already cramped in there with one person, I don’t think it’s very safe…”  A worried frown spread across his face, but his apprehension did nothing to alleviate the adrenaline coursing through his bloodstream.  

Inaho settled himself into his seat, and carefully angled it back so there was just enough room for Slaine to join him.  “Then ride me.”

“Are you joking?” said Slaine, slack-jawed.  “We’re going into a battle right now.  You should understand this better than anyone!  Besides,” his voice lowered to a mumble, “if we die because we were too busy having sex, the UFE will lose a good pilot for a bad reason.”  

The brunet fixed him with an emotionless stare.  “I’m not joking.  I’m still hard, too,” he responded, like it was the most obvious thing in the world.

Slaine was suddenly intensely envious of the fact that Inaho could say things like that while remaining so cool and collected.  “Well, will we win the fight?” he asked, trying bring their focus back to what was really important.  Someone had to make an effort, halfhearted as it was.

“Definitely,” Inaho affirmed, and Slaine knew it wasn’t out of arrogance.  “It’s not difficult to beat a Martian Kataphrakt once you figure out how it works.  We’ll be perfectly safe, Slaine.  Don’t try to change the subject.”

“Fine, we’ll do it,” Slaine conceded, gingerly stepping into the KG-6.  It didn’t take much coaxing.  

He knew that it was monumentally stupid, but at this point it was nearly impossible to deny the urge.  The gloves came off again.  Inaho, ever practical, proffered the lube.  

He unfastened his belt and slid his pants down, then, with a shaky breath, mounted Inaho’s cock.  It went in a little more easily this time, but it still took him a moment to adjust.  Inaho wrapped his arms around Slaine’s waist, holding him against his chest reassuringly.

“Take your time,” the younger boy said.  “We’ll go at your pace.”

A crackle over the intercom as Warrant Officer Kaizuka Yuki briefed them.  “Mustang Platoon, there’s two Martian Kats at eleven o’clock.  I’ll cover you.  Looks like a similar type to what we’ve faced before, so let’s try to finish them before they call reinforcements.”  

“Understood, Yuki-nee,” Inaho said, into the mic.  “I’m disconnecting now.”  

“Inaho!” Amifumi Inko, a normal, rational KG-7 pilot, yelled indignantly.  “You can’t just - ” she was cut off by static as Inaho unflinchingly switched all comms off.  

Slaine would have been more understanding (because who _did_ that?!), but he absolutely did not want anyone to overhear his embarrassingly loud moans.  He settled into a rhythm, rocking and grinding on top of Inaho in time to the Kataphrakt’s movements.  It was nice and slow, and he was happy to be in control for once.  

The battle commenced.

“Ahh… you can evade that then fire HE rounds,” Slaine suggested.  “ _I-Inaho_.”  The name came out in a hiss, punctuated with heavy liquid lust.  He pressed his palms into his thighs, feeling each tremor that ran through his body.  “Er, their reload time is quite slow, so we can use that to our advantage.”

“Maybe…”  Inaho’s breathing grew laboured as well, and he shifted in his seat.  “Ugh… I’ll need to exploit their weak point and preserve ammunition.”

He’d never felt so intoxicated.  It was irresponsible and exhilarating and nothing like he’d ever experienced before.  His heart was racing and he was throbbing unbearably, the sheer recklessness only serving to arouse him more.  

“Hold on, Bat.”  Inaho’s voice was oddly strained, but his piloting was still impeccable.  He input a complex maneuver and dodged a large wave of incoming fire, then shot off a perfectly aimed stream of bullets that stopped the enemy in its tracks.  All of this was performed with casual indifference, as per usual.  His next words held a certain vulnerability, though, which Slaine found to be incredibly enticing.  “Please… hurry up, if you can.  I’m getting close, I think.”

Slaine complied, bucking his hips against Inaho’s shaft, a new sense of urgency overtaking him.  He could feel his insides clamping down on Inaho, the need for friction becoming increasingly more frantic and desperate as he sped up his pace in quick, shallow movements.  

“Aahhh…!”  He gripped his own cock, slick and leaking with unbridled desire.  

“Try not to mess up the control board,” Inaho said, almost as an afterthought, as though he were giving Slaine basic piloting instructions.  

He tipped his head back and trembled violently, arching his back as he came.  Thick strings of cum spilled onto his fingers and he cried out, crushing himself to Inaho’s chest and shivering uncontrollably.  “Inaho!”

“...Slaine,” the younger boy uttered, going limp beneath him as he brought the Kataphrakt to a halt.   

He twisted around to straddle Inaho, pressing a chaste, tired kiss to the brunet’s mouth.  They sat there, unmoving, their heavy breaths the only sound in the Sleipnir.  

“Oh,” said Inaho, glancing at the battle map.  “We won.  All Martian Kataphrakts in the immediate vicinity are now inoperable.”

“Next time,” Slaine murmured hoarsely, his voice barely above a whisper, “let’s take the Sky Carrier.”

**Author's Note:**

> Thank you for reading! First time I wrote an explicit story without my face setting on fire! Martians sure know how to cockblock, huh. So uh, this was written solely for the end imagery of Godnaho ~~and his plot armour~~ super casually wrecking all the enemy Kats while Slaine just grinds on his lap. That’s the point of mecha, right? Man, Inaho is so based I can't even be mad haha. In other news, I guess that the KG-6 model I preordered has now been christened :P (next up, Sky Carrier and Tharsis?)
> 
> Have a lovely day ♡


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